From: NeilBrown <neilb@suse.de>
Date: Tue, 14 Sep 2010 05:44:41 +0000 (+1000)
Subject: Change readpage to use ->chain instead of ->lru
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=66dc1469619bba505bd285631a2e3538f7a4dd45;p=LaFS.git

Change readpage to use ->chain instead of ->lru

->lru is rather overused, and ->chain is certainly never used on
non-B_Valid blocks, so convert readpage to use chain instead.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/io.c b/io.c
index 138cd98..ca0e350 100644
--- a/io.c
+++ b/io.c
@@ -440,11 +440,10 @@ blocks_loaded(struct bio *bio, int error)
 {
 	struct block *bhead = bio->bi_private;
 
-	while (!list_empty(&bhead->lru)) {
-		struct block *b = list_first_entry(&bhead->lru,
-						   struct block,
-						   lru);
-		list_del_init(&b->lru);
+	while (bhead->chain) {
+		struct block *b = bhead->chain;
+		bhead->chain = b->chain;
+		b->chain = NULL;
 		bio->bi_private = b;
 		block_loaded(bio, error);
 	}
@@ -535,13 +534,13 @@ lafs_load_block(struct block *b, struct bio *bio)
 
 		return 0;
 	}
+	LAFS_BUG(b->chain != NULL, b);
 	if (bio->bi_size == 0) {
 		bio->bi_sector = sect;
 		bio->bi_bdev = bdev;
 		bio_add_page(bio, page, fs->blocksize, offset);
 		bio->bi_private = b;
 		bio->bi_end_io = blocks_loaded;
-		BUG_ON(!list_empty(&b->lru));
 		return 0;
 	}
 	if (bio->bi_sector + (bio->bi_size / 512) != sect
@@ -550,7 +549,8 @@ lafs_load_block(struct block *b, struct bio *bio)
 		return -EINVAL;
 	/* added the block successfully */
 	headb = bio->bi_private;
-	list_add_tail(&b->lru, &headb->lru);
+	b->chain = headb->chain;
+	headb->chain = b;
 	return 0;
 }
 
diff --git a/state.h b/state.h
index 57bdddf..0bc3cba 100644
--- a/state.h
+++ b/state.h
@@ -378,7 +378,8 @@ struct block {
 					 * in storage (i.e. in another snapshot)
 					 */
 
-	struct block		*chain; /* on list of unincorporated changes */
+	struct block		*chain; /* on list of unincorporated changes, or list of blocks
+					 * being read in */
 
 #if DEBUG_REF
 	struct ref {int cnt; char *name; } holders[16];